SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e29360169f9e36d75ae46c54bba4b77cd16cd3cec3e2a97d1a4b1adc8eceb3a6' 
  AND token = 'hfFTBnWrp/PeZOfdLmmXvprnxPgGms00KgRZzYYk9/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}